Tears along the vaginal wall can be a common problem during childbirth, particularly when an expectant mother pushes the baby towards the birth canal prior to full dilation of the mother's cervix. This involves tearing the tissue of the cervix and the vagina wall. When this occurs, the mother may require post-birth surgery to stitch up the torn tissue, often under general anesthetic.
Tears of the vagina walls, the perinium (which is the area of tissue between the vagina and the anus), and the anus commonly occur during vaginal delivery. Natural perineal tears are referred to by their severity. First-degree tears involve tearing only the skin. Second-degree tears involve tearing muscle. Third-degree tears involve tearing the external anal sphincter muscle. Fourth-degree tears further involve tearing the rectal mucosa.
Sometimes the perinium is purposely cut by a doctor performing an episiotomy, which is an incision into the perinium to enlarge the size of the vaginal opening. A episiotomy is similar to a first or second-degree natural tear.
All of the above tearing or incisions usually require post-delivery operations to stitch up the area. Stitching fourth-degree tears is particularly difficult using known specula given that fourth-degree tears typically extend from the vagina wall all the way to the rectum.
A variety of surgical retractors are known for use during gynaecological examinations and are commonly called specula for this purpose. Specula generally have blades that are moveable between a closed position where the blades are in close proximity to each other and at least one open position wherein the blades are displaced with respect to each other to create an enlarged area within the vaginal canal near the cervix. The base end of each blade is typically connected to the body of the speculum around an enclosed opening of a limited size. A speculum can be adjusted so that the distance between the blades is expanded, allowing a physician to view and work with an expanded vaginal canal.
Existing specula can aid a physician in conducting inspections of the vagina and cervix. However, known speculum have shortcomings when used for surgery, particularly for surgery involving tears along the vaginal wall or cervix.
To stitch up tears of the cervix and vagina wall, it is common for doctors to use a speculum with blades that open to expand the vaginal cavity. This creates a larger opening near the cervix and a smaller opening near the entrance to the vagina.
The only access to a dilated vagina through a typical speculum is through an opening in the speculum that is bordered on all sides by parts of the speculum. This is an opening of limited size. For this reason, it is often difficult for a surgeon to have enough room to stitch a patient's cervix and vagina wall. A typical speculum encumbers or prevents a surgeon from stitching up the entrance of the vagina without removing the speculum.
An example of an existing speculum that encumbers the entrance of the vagina is disclosed in U.S. Pat. No. 3,985,125 issued to Rose. The Rose speculum has two limb members that are moveable with respect to each other. At the rear end of the main limb member is a yoke having two side walls and a free end portion. The only access to the dilated vagina using the Rose speculum is through an opening that is bordered by the main limb member, the side walls of the yoke, and the lower limb member.
U.S. patent application publication No. 2002/0022771 filed by Diokno et al. discloses a vaginal speculum with removable blades. Diokno discloses an upper blade that is pivotally adjustable with respect to the position of the remaining speculum to allow for a larger opening inside the vaginal cavity than at the entrance. When the Diokno blades are not removed, the entrance opening is of a fixed size. When at least one blade is removed, a remaining lower part can be used as a spatula.
Another known speculum uses scissor-type arms. U.S. Pat. No. 5,785,648 to Min discloses a speculum with manually operated scissor arms that have replaceable blade members. The speculum blades include a self-contained fiber optic light source. The Min invention does not disclose the ability to pivotally adjust the angle of the blades.
There exists a need for a surgical retractor suitable for operations wherein the displacement between two blades is both laterally expandable and pivotally adjustable. There is further a need for a surgical retractor that does not significantly encumber the vagina entrance when the retractor is in position for gynaecological operations.